Ketone derivatives include lactones and lactams. For example, carolic acid and carolynic acid are known as natural lactones and compounds disclosed in J. Chem. Soc. Perkin Trans. I, 14, 1485-1491 (1976) and Synth. Comm., 22(6), 809-816 (1992) are known as non-naturally derived compounds. In addition, compounds disclosed in J. Org. Chem., 40(13), 1927 (1975), Tetrahedron Lett., 33, 2821 (1975), Chem. Pharm. Bull., 32, 3724 (1984), Tetrahedron Lett., 163 (1973), and the like are known as compounds having the following general formula (I') wherein R.sub.4 is an ester group: ##STR2##
Lactams of the general formula (I) wherein X is nitrogen are disclosed in Japanese Patent Laid-Open Nos. 2-279691, 4-49289, 2-48591, and 1-313488, Chem. Pharm. Bull., 32(10), 4197-4204 (1984), Pharmazie, 43(7), 473-474 (1988), Monatsh. Chem., 123(1-2), 93-98 (1992), J. Inorg. Biochem., 24(3), 167-181 (1985), J. Am. Chem. Soc., 107(18), 5219-5224 (1985), J. Org. Chem., 50 (8), 1344-1346 (1985), and Chem. Rev., 95, 1981-2001 (1995).
Applications of lactones include, for example, a compound disclosed in Japanese Patent Laid-Open No.5-43568 and EP 0508690, which is known as an anti-inflammatory agent inhibiting phospholipase A2, a compound disclosed in Archive des Pharmazie (Weinhelm, Ger.) (1983), 316(2), 115-120, which is known as an anticoagulant, and a compound disclosed in Journal of Antibiotics (1994), 47(2), 143-7, which is known as an anti-AIDS agent inhibiting HIV-protease.
Applications of lactams include, for example, a compound disclosed in Chem. Pharm. Bull., 32(10), 4197-4204 (1984), which is known as an agent having antibacterial activity, and a compound disclosed in J. Antibiot., 33(2), 173-181 (1980), which is known as an anaerobic antibiotic. However, no ketone derivative has been known to have hematopoietic activity.
An object of the present invention is to provide ketone derivatives, medical agents which have such ketone derivatives or pharmaceutically acceptable salts thereof as an active ingredient, in particular, a hematopoietic agent used for preventing or treating cytopenia caused by cancer chemotherapy, radiation therapy, bone-marrow transplantation, drug therapy, immunological disorders, anemia, or the like.